Shimano M70CT4 V-Brake Shoe Insert. M70CT4: Only for sidewall-machined rims; performs especially well in wet conditions and may pass DIN standard; tends to be low noise, low rim wear and fade.
These pads do not hold grit and grind down your rims. The other style of Shimano M70R2 severe condition pads drove me crazy because they were so soft they held grit and small rocks embedded so I would hear a horrible grinding noise when braking. The M70CT4 pads for machined sidewall rims do not hold grit. They work great in wet or dry conditions. They last a long time. They also worked fine on non machined sidewall aluminum rims but they were high quality rims.